While Avoiding Back Strain
The proper way of picking up something is different ... IF ... the box or object has no convenient handles on it (which is more often the case). What you must do is go to the ground on one knee, pick the box up and set it on your other knee ... then ... stand up with the bulk of the weight of the object resting on that knee. Believe me this is very, very much easier. Try it the next time you have to pick up a 50 pound box of clay or a box of typing paper.
If you intend to pick up a small object, don't stoop for it. Just use your leg as a "tail" and cantilever your upper torso. It's why dinosaurs had tails. It counter-balances the front of the body so that the animal can stand on its hind legs. In fact, having a big lard-ass tail is proof that the animal stands on its back legs. If it never did, it wouldn't need a tail.
Never pick up a penny off the floor as they are not worth the effort. Let's say you get a job picking up pennies at one cent per penny picked up one at a time. How much do you think you could make in a day? If you needed $100 per day, you'd have to pick up 10,000 pennies ... that's 10,000 deep knee bends per day. See what I mean? How about nickels? That's only 2,000 deep knee bends per day. Even going down for dimes is problematic ... unless you're just doing it for the exercise. Quarters ... hmmmm ... maybe. But use the above cantilever technique. It's far less stressful.
And if you are Bill Gates, you don't even bother for Thousand Dollar Bills. In fact, he undoubtedly has someone to wipe his ass for him ... or ... does ... he ????